在 Mockito 中模拟静态 class

Question

我有如下内容：

    public class Foo {

    public static String getValue(String key) {
        return key + "_" + System.currentTimeMillis();
    }
}

现在我需要一个测试用例，这是我尝试的方式：

@Test
public void testFoo() {
   PowerMockito.mockStatic(Foo.class);
    PowerMockito.when(Foo.getValue("123")).thenReturn("abcd");
    PowerMockito.verifyStatic();

}

当我运行测试用例时，我得到这个：

org.mockito.exceptions.misusing.MissingMethodInvocationException: 
when() requires an argument which has to be 'a method call on a mock'.
For example:
    when(mock.getArticles()).thenReturn(articles);

Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
   Those methods *cannot* be stubbed/verified.
   Mocking methods declared on non-public parent classes is not supported.
2. inside when() you don't call method on mock but on some other object.

    at org.powermock.api.mockito.PowerMockito.when(PowerMockito.java:495)

我做错了什么吗？

请指教

Answer 1

您能否确认您已将 @PrepareForTest(Foo.class) 注释添加到您的测试 class 中，如所列 on the PowerMock site, and that you're using the PowerMockRunner JUnit4 运行器？

静态方法是使用静态分派调用的，而不是使用 Java 的正常多态性和方法覆盖的动态分派。要替换实现，PowerMock 需要在测试开始运行之前加载替换 class，而运行器和注释会实现这一点。

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